Fix a wrong logical AND (&&) used for the range check of CSR MMIO.

Spotted nicely by gcc -Wlogical-op flag:
  drivers/gpu/drm/i915/intel_csr.c: In function ‘finish_csr_load’:
  drivers/gpu/drm/i915/intel_csr.c:353:41: warning: logical ‘and’ of mutually exclusive tests is always false [-Wlogical-op]

Fixes: eb805623 ('drm/i915/skl: Add support to load SKL CSR firmware.')
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>